Vitamin D Treatment Guidelines

Measurement of 25(OH)D in the circulation is the best diagnostic test for determining a person’s vitamin D status.1 Usually 1,25(OH)2D levels in the circulation are normal or elevated in vitamin D deficient patients and thus should not be used to determine a person’s vitamin D status. However, 1,25(OH)2D measurement is of value in acquired and inherited disorders of vitamin D metabolism including pseudovitamin D deficiency rickets, vitamin D resistant rickets, granulomatous disorders and some lymphomas.1 The Institute of Medicine (IOM) and the Endocrine Society have defined vitamin D deficiency as it relates to bone health as a 25(OH) D less than 20 ng/mL (50 nmol/L).7,8 However, the Endocrine Society concluded that vitamin D improves muscle function and based on many association studies may also have some additional benefit in reducing several chronic illnesses. As a result, they defined vitamin D insufficiency as a 25(OH)D of 21–29 ng/mL.